• Lukas Wunner's avatar
    serial: pl011: Fix oops on -EPROBE_DEFER · 27afac93
    Lukas Wunner authored
    If probing of a pl011 gets deferred until after free_initmem(), an oops
    ensues because pl011_console_match() is called which has been freed.
    
    Fix by removing the __init attribute from the function and those it
    calls.
    
    Commit 10879ae5 ("serial: pl011: add console matching function")
    introduced pl011_console_match() not just for early consoles but
    regular preferred consoles, such as those added by acpi_parse_spcr().
    Regular consoles may be registered after free_initmem() for various
    reasons, one being deferred probing, another being dynamic enablement
    of serial ports using a DeviceTree overlay.
    
    Thus, pl011_console_match() must not be declared __init and the
    functions it calls mustn't either.
    
    Stack trace for posterity:
    
    Unable to handle kernel paging request at virtual address 80c38b58
    Internal error: Oops: 8000000d [#1] PREEMPT SMP ARM
    PC is at pl011_console_match+0x0/0xfc
    LR is at register_console+0x150/0x468
    [<80187004>] (register_console)
    [<805a8184>] (uart_add_one_port)
    [<805b2b68>] (pl011_register_port)
    [<805b3ce4>] (pl011_probe)
    [<80569214>] (amba_probe)
    [<805ca088>] (really_probe)
    [<805ca2ec>] (driver_probe_device)
    [<805ca5b0>] (__device_attach_driver)
    [<805c8060>] (bus_for_each_drv)
    [<805c9dfc>] (__device_attach)
    [<805ca630>] (device_initial_probe)
    [<805c90a8>] (bus_probe_device)
    [<805c95a8>] (deferred_probe_work_func)
    
    Fixes: 10879ae5 ("serial: pl011: add console matching function")
    Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
    Cc: stable@vger.kernel.org # v4.10+
    Cc: Aleksey Makarov <amakarov@marvell.com>
    Cc: Peter Hurley <peter@hurleysoftware.com>
    Cc: Russell King <linux@armlinux.org.uk>
    Cc: Christopher Covington <cov@codeaurora.org>
    Link: https://lore.kernel.org/r/f827ff09da55b8c57d316a1b008a137677b58921.1597315557.git.lukas@wunner.deSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    27afac93
amba-pl011.c 71.5 KB